The present invention relates to an image processing system, a program, an information storage medium, and an image processing method.
A technique is known in the art of preparing an image for the left eye, taken by a camera that is equivalent to the left eye, and an image for the right eye, taken by a camera that is equivalent to the right eye, then synthesizing these images by anaglyph processing or the like to obtain a stereoscopic image (printed material for stereoscopic viewing), as disclosed in Japanese Patent Application Laid-Open No. 2000-56411, by way of example.
There are three physiological functions that enable a human being to experience the feeling of three dimensions: (1) binocular parallax (difference in the line-of-sight angles of the eyes) that creates an offset in the imaging of the retinas due to the spatial separation of the left and right eyes, (2) convergence, which is a function that directs the eyes inward, and (3) focal adjustment (focal distance) of the thickness of a crystal body in answer to distance to the object. The human being processes the three physiological functions of binocular parallax, convergence, and focal adjustment within the brain, to produce the stereoscopic feeling.
The relationships between these three physiological functions are usually linked within the brain. If an error or inconsistency should arise in these relationships, therefore, the brain will try to force these stereoscopic linkages, which creates a situation in which the image feels unnatural or the viewer cannot recognize it as a stereoscopic image.
Incidentally, stereoscopic viewing in the prior art uses only binocular parallax and convergence for representing a stereoscopic view. For that reason, the focus (focal distance) remains substantially constant within the surface of the stereoscopic image (printed material for stereoscopic viewing), so that offsets in binocular parallax or convergence occur at substantially all the locations in the stereoscopic image, making it impossible to implement a stereoscopic view that is easy for the brain of a human being to see.
The stereoscopic image is obtained by synthesizing an image for the left eye and an image for the right eye that have been obtained by photographing a subject with a camera, by way of example. If there is any warping in the image for the left eye and the image for the right eye, therefore, the viewer looking at the stereoscopic image will feel that it is unnatural, or the image may become difficult to be seen stereoscopically.